WASHINGTON — He canceled a trip to a cemetery in France where American soldiers from World War I are buried. He did not go to the observance at Arlington National Cemetery on Veterans Day. He has not visited American troops in Iraq or Afghanistan.
And shortly after becoming commander in chief, President Trump asked so few questions in a briefing at MacDill Air Force Base in Tampa, Fla., that top military commanders cut the number of prepared PowerPoint slides to three — they had initially planned 18 — said two officials with knowledge of the visit.
The commanders had slotted two hours for the meeting, but it lasted less than one.
Rhetorically, Mr. Trump has embraced the United States’ 1.3 million active-duty troops as “my military” and “my generals” and has posted on Twitter that under his leadership, the American armed forces will be “the finest that our Country has ever had.” But top Defense Department officials say that Mr. Trump has not fully grasped the role of the troops he commands, nor the responsibility that he has to lead them and protect them from politics.
“There was the belief that over time, he would better understand, but I don’t know that that’s the case,” said Col. David Lapan, a retired Marine who served in the Trump administration in 2017 as a spokesman for the Department of Homeland Security. “I don’t think that he understands the proper use and role of the military and what we can, and can’t, do.”
On Thursday, Mr. Trump spent less than an hour in a pre-Thanksgiving visit to the Marine Barracks in Washington, three and a half miles from the White House, the home of the Marine commandant and units assigned to ceremonial and security missions in the capital. The president then returned to the White House to briefly address a group of veterans.
“I think the vets, maybe more than anybody else, appreciate what we are doing for them,” Mr. Trump said.
On Wednesday, it was Defense Secretary Jim Mattis who visited American troops on the border with Mexico in the latest military deployment under Mr. Trump’s watch. Mr. Mattis traveled to Base Camp Donna in Texas, where he met with troops who have been webbing concertina wire to keep out an approaching caravan of migrants the president has likened to an “invasion.”
Pentagon officials have privately derided the deployment of nearly 6,000 active-duty troops as a morale killer and an expensive waste of time and resources, put in motion by a commander in chief determined to get his supporters to the polls. The troops, who are providing only logistical support, will be there until Dec. 15.
“It’s always better to come down and see it for real,” Mr. Mattis said in talking with troops.
Like two recent former presidents, Barack Obama and Bill Clinton, Mr. Trump came to office without having served in the military. Former President George W. Bush served in the Air National Guard during the Vietnam War but never left the country, and questions were raised about how often he reported for duty. All three had complicated relationships with the armed forces.
Mr. Clinton, a Vietnam War protester who avoided the draft, was initially uncomfortable with the generals. Mr. Bush trusted the military leadership in Iraq for years before finally overruling what he considered their losing strategy. Mr. Obama was convinced from the beginning that the military was trying to box him into sending more troops to Afghanistan.
Mr. Trump, who received a deferment from Vietnam because of bone spurs in his heel, came to office with a reverence for the idea of the military. He followed through by appointing generals as defense secretary, White House chief of staff and twice as national security adviser.
But unlike past Republican presidents, Mr. Trump has seen little value in the long American deployments to Afghanistan, Iraq and other conflicts. He considers them a waste of money and lives, and has told advisers that the people in the countries where troops are stationed are not really friends of the United States.
One reason he has not visited troops in war zones, according to his aides, is that he does not really want American troops there in the first place. To visit, they said, would validate missions he does not truly believe in.
Mr. Bush went four times to Iraq and Mr. Obama went once, three months after his inauguration. Both presidents made four trips each to visit troops in Afghanistan.
Mr. Trump has also not made special trips to seek out deployed troops elsewhere, as his predecessors did. President George Bush was a lame-duck president, three weeks away from Mr. Clinton’s inauguration, when he traveled on New Year’s Day 1993 to shake hands with troops deployed to Somalia.
Mr. Trump has also appeared to avoid responsibility as commander in chief when a Navy SEAL, William “Ryan” Owens, a chief warfare special operator, was killed last year in Yemen.
The president seemed to blame his generals for the death, in a mission that he had authorized, when he told Fox News that military commanders “came to see me and they explained what they wanted to do, the generals, who are very respected.”
The president continued: “And they lost Ryan.”
Mr. Trump’s aides said that he was so personally distraught knowing that the SEAL had died under his command that he flew to Dover Air Force Base in Delaware for the return of the body — something presidents generally have not done for a single death.
But last weekend in France, Mr. Trump skipped a visit to a cemetery of American World War I soldiers killed during the Battle of Belleau Wood because, Mr. Trump said this week in a tweet, rain grounded his helicopter and the Secret Service told him driving was too disruptive to traffic. Gen. Joseph F. Dunford Jr., the chairman of the Joint Chiefs of Staff, and John F. Kelly, the Marine general turned White House chief of staff, went instead.
Advisers said Mr. Trump would have been willing to overrule the Secret Service and go by road had anyone urged him to, and that he was furious that no one warned him it would be a political disaster to skip the trip.
Mr. Trump did visit another cemetery in Paris the next day.
His decision days before the midterm elections to send troops to respond to what he insisted was a crisis at the southwestern border remains of deep concern to Defense Department officials. He has taken an unusually keen interest in the issue — so much so, military officials said, that Mr. Trump has repeatedly called Gen. Terrence J. O’Shaughnessy, the head of the Pentagon’s Northern Command who oversees operations on the nation’s borders, for updates over the past few weeks.
“If a president routinely and cynically leverages our nation’s armed forces for short-term political advantage, the professional ethos” of the officers corps will be degraded, said Karl W. Eikenberry, a retired three-star Army general and a former commander of American forces in Afghanistan. “This, in turn, would threaten one of the foundational principles of our republic — that our military must remain outside of politics.”
At one point during Mr. Mattis’s visit to the border on Wednesday, a soldier asked him the goals of the mission. “Short term, get the obstacles in,” the defense secretary replied. “Long term, it is somewhat to be determined.”
Mr. Trump has also alarmed Defense Department officials with seemingly off-the-cuff remarks about military matters.
In April, the president told reporters that “it’s time” to bring American forces home from Syria — an announcement that stunned the Pentagon, Defense Department officials said, because Syria was at the heart of the battle against the Islamic State and a linchpin to Mr. Trump’s national security strategy that called for confronting Iran. Leaving Syria would cede ground to Iran and, potentially, Russia. It would also abandon local fighters who have been the United States’ strongest allied ground forces against the Islamic State in Syria.
The response at the Pentagon was a deliberate silence, Defense Department officials said, who anticipated that Mr. Trump would not follow up and would instead move on to other topics, which he did.
In June, Mr. Trump canceled planned joint military exercises with South Korea without consulting the Pentagon and described the exercises as “war games,” undercutting decades of Defense Department assertions that the drills were not meant to be provocative.
Yet Mr. Trump loves much of the spectacle of commander in chief: cheering troops in a hangar, the tanks and ships and planes, a military parade he proposed for Veterans Day in Washington. He has also boasted repeatedly about securing billions of additional dollars for the Pentagon.
Military officers feel torn between Mr. Trump’s efforts to win them the money they felt deprived of during the Obama years and being used as political props for speeches that sound more like rallies.
“They like having robust funding for the last year; they like that,” said Michèle A. Flournoy, a former under secretary of defense who turned down a chance at the No. 2 job at the department under Mr. Trump. “But I think a lot of military people are deeply disturbed by the degree of partisanship and division.”
Military leaders resist criticizing a commander in chief publicly, but the silence of some of them has spoken volumes.
“My father was a career Army officer,” said James R. Clapper, a retired Air Force general who was the director of national intelligence during the Obama administration and is now a prominent critic of Mr. Trump. “It is part of my being to want to respect and support the president as commander in chief.”
He added, “This one makes that very hard for me.”